Deep structure of the Demerara Plateau: From a volcanic margin to a Transform Marginal Plateau

Museur, T.; Graindorge, David; Klingelhoëfer, Frauke; Roest, W. R.; Basile, Christophe; Loncke, Lies; Sapin, François

doi:10.1016/j.tecto.2020.228645

Cited by 24 publications

(57 citation statements)

References 66 publications

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“…Along the eastern border of the basin, the LAA has been imaged by wide-angle seismic data and here an origin of the arc from volcanic products intruding a thick plateau crust PADRON ET AL. (Afilhado et al, 2015;Gailler et al, 2009;Moulin et al, 2015); (c) Demerara (Museur et al, 2020); (d) this study; (e) Algeria (Badji et al, 2015;Klingelhoefer et al, 2014); (f) Nova Scotia (Funck et al, 2004); (g) Morocco (Biari et al, 2015). TOC, Transition Ocean-Continent, TAO, Transition Arc-Ocean.…”

Section: Nature Spreading Direction and Extent Of The Oceanic Crust In The Grenada Basinmentioning

confidence: 82%

“…A second example of transform or highly oblique opening is the Demerara Plateau in the Equatorial Atlantic (Figure 17c). Here opening was accompanied by heavy volcanism leading to the deposition of large amounts of seaward dipping reflector (SDR) packages building a large part of the plateau (Museur et al., 2020; Reuber et al., 2016). Some volcanic edifices are identified in our study region (Garrocq et al., 2021) and the sedimentary sequences might contain volcano‐sedimentary layers.…”

Section: Discussionmentioning

confidence: 99%

“… Comparison of the GA02 velocity model with other margins and plateaus: (a) and (b) Liguro‐Provencal Basin (Afilhado et al., 2015; Gailler et al., 2009; Moulin et al., 2015); (c) Demerara (Museur et al., 2020); (d) this study; (e) Algeria (Badji et al., 2015; Klingelhoefer et al., 2014); (f) Nova Scotia (Funck et al., 2004); (g) Morocco (Biari et al., 2015). TOC, Transition Ocean‐Continent, TAO, Transition Arc‐Ocean.…”

Section: Discussionmentioning

confidence: 99%

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Deep Structure of the Grenada Basin From Wide‐Angle Seismic, Bathymetric and Gravity Data

et al. 2021

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The Grenada back-arc basin is located between the Aves Ridge, which hosted the remnant Early Paleogene "Great Caribbean Arc," and the Eocene to Present Lesser Antilles Arc. Several earlier studies have proposed different modes of back-arc opening for this basin, including N-S and E-W directions. The main aim of this study is to constrain the circumstances leading to the opening of the basin. Three combined wide-angle and reflection seismic profiles were acquired in the Grenada basin. The final velocity models from forward travel time and gravity modeling image variations in thickness and velocity structure of the sedimentary and crustal layers. The sedimentary cover has a variable thickness between 1 km on top of the ridges to ∼10 km in the basin. North of Guadeloupe Island, the crust is ∼20 km thick without significant changes between Aves Ridge, the Grenada basin, and the Eocene and present Lesser Antilles arc. South of Guadeloupe Island the Grenada basin is underlain by a oceanic crust of mainly magmatic origin over a width of ∼80 km. Here, the western flank of the Lesser Antilles Arc, the crust is 17.5-km thick. The velocity structure of the Lesser Antilles Arc is typical of volcanic arcs or oceanic plateaus. West of the basin, the crust thickens to 25 km at Aves Ridge in an 80-100 km wide arc-ocean transition zone. The narrowness of this transition zone suggests that opening might have proceeded in a direction oblique to the main convergence. Opening probably was accompanied by moderate volcanism.

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Section: Nature Spreading Direction and Extent Of The Oceanic Crust In The Grenada Basinmentioning

confidence: 82%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Deep Structure of the Grenada Basin From Wide‐Angle Seismic, Bathymetric and Gravity Data

et al. 2021

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“…A second example of transform or highly oblique opening is the Demerara Plateau in the Equatorial Atlantic (Figure 17c). Here opening was accompanied by heavy volcanism leading to the deposition of large amounts of seaward dipping reflector (SDR) packages building a large part of the plateau (Museur et al, 2020;Reuber et al, 2016). Some volcanic edifices are identified in our study region (Garrocq et al, 2021) and the sedimentary sequences might contain volcano-sedimentary layers.…”

Section: Comparison Of the Grenada Basin Margins With Other Continental Marginsmentioning

confidence: 84%

“…Figure 17. Comparison of the GA02 velocity model with other margins and plateaus: (a) and (b) Liguro-Provencal Basin(Afilhado et al, 2015;Gailler et al, 2009;Moulin et al, 2015); (c) Demerara(Museur et al, 2020); (d) this study; (e) Algeria(Badji et al, 2015;Klingelhoefer et al, 2014); (f) Nova Scotia(Funck et al, 2004); (g) Morocco(Biari et al, 2015). TOC, Transition Ocean-Continent, TAO, Transition Arc-Ocean.…”

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confidence: 95%

Deep structure of the Grenada Basin from wide-angle seismic, bathymetric and gravity data

Padrón¹,

Klingelhoëfer²,

Marcaillou

et al. 2021

Preprint

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<p>Studying back-arc basins, where sedimentation is less deformed than in the forearc, provides complementary information about formation and tectonic evolution of subduction zones. At the Lesser Antilles subduction zone, the North and South American plates are subducting underneath the Caribbean plate at a velocity of 2 cm per year. The crescent-shaped Grenada back-arc basin is located between the Aves Ridge, which hosted the remnant Early Paleogene &#8220;Great Caribbean Arc&#8221;, and the Eocene to present Lesser Antilles Arc. In this study, based on wide-angle data, we provide constraints about lateral variations in basement thickness and velocity structure in the Lesser Antilles back-arc, and to a lesser extend in the arc and forearc domain, constraining for the first time the extent of oceanic crust in the Grenada Basin and shed light on the structure and compositions of the basin&#8217;s margins.</p><p>Three combined wide-angle and reflection seismic profiles, together with gravity and bathymetric data, were acquired in the Lesser Antilles back-arc basin. Direct modeling techniques were applied to the wide-angle seismic data in order to include shallow structures imaged by the coincident reflection seismic data. The resulting velocity models were additionally constrained by gravity modeling and synthetic seismogram calculation. The final models from direct modeling image variations in thickness and velocity structure of the sedimentary and crustal layers to a depth of up to 35 km. The sedimentary cover has a variable thickness from less than a kilometer on top of the ridges to nearly 10 km in the basin. North of Guadeloupe Island, the crust is ~20 km thick from back-arc to forearc, without significant change between the Aves Ridge, the Eocene and present Lesser Antilles volcanic arc. While based on the seismic velocities, the southern part of the basin is underlain by a 6.5-7 km thick crust of of mainly magmatic origin over a width of ~80 km, the northern part is underlain by thinned continental crust. At the western flank of the Lesser Antilles Arc, the crust is 17.5-km thick, about 5 km thinner than north of Martinique island. The velocity structure is typical of volcanic arcs or oceanic plateaus. Between Aves Ridge and the Grenada basin the crust thins in a 80-100 km wide transition zone. No anomalous high velocities indicating the presence of exhumed upper mantle material were detected at the transition zone. This narrow E-W arc-ocean transition zone suggests that opening might have proceeded in a direction highly oblique to the main convergence.</p>

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Influence of Hotspot Magmatism on Breakup Modes and Oceanic Crust Architecture along a Passive Margin: Insights from Mauritania/Senegal/Guinea Basin

Sapin

Maurin

2022

Preprint

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Deep structure of the Demerara Plateau: From a volcanic margin to a Transform Marginal Plateau

Cited by 24 publications

References 66 publications

Deep Structure of the Grenada Basin From Wide‐Angle Seismic, Bathymetric and Gravity Data

Deep Structure of the Grenada Basin From Wide‐Angle Seismic, Bathymetric and Gravity Data

Deep structure of the Grenada Basin from wide-angle seismic, bathymetric and gravity data

Influence of Hotspot Magmatism on Breakup Modes and Oceanic Crust Architecture along a Passive Margin: Insights from Mauritania/Senegal/Guinea Basin

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